(In this application, we propose a multi-disciplinary approach for identification and further development of lead molecules already in hand against DENV serine protease (DENV NSSpro) and RNA-dependent RNA polymerase (DENV RdRP). The product development plan would involve completion of following three specific aims and milestones. In aim 1, we propose to identify new inhibitors of the viral NS3 protease and compounds that block NS3/NS5 interaction by high throughput screening (HTS) and by virtual screening. The novel series of compounds have been have been identified to date as promising protease inhibitors. Compounds will be further optimized by iterative medicinal and combinatorial chemistry, molecular modeling, to obtain potent and selective drug-like lead molecules. In aim 2, a novel and potent antiviral agent: that we termed 7DA6MEPN that targets the NS5 RdRP has been identified to inhibit DENV replication. Additional analogues of 7-deaza-6-methylpurine ribonucleoside will be synthesized and evaluated to further improve the efficacy and therapeutic index of this promising antiviral agent. In aim 3, compounds identified and synthesized under aims 1 and 2 will be further evaluated for inhibitory potency by in vitro enzyme assays (IC50 values), cytotoxicity assays (CC50 values), reporter replicon-based as well as virus infectivity assays (EC50) in mammalian cell culture. Selected compounds showing inhibition in the nM range will be analyzed by ADME/TOX assays.